#77 achieve 100% test coverage for indicators - aroon
refactor to ensure that what instantiating an indictor with fixed length source data no storage allocation occurs if there is not enough data to cover the lookback
#77 achieve 100% test coverage for indicators - aroonosc
#77 achieve 100% test coverage for indicators - atr
#77 achieve 100% test coverage for indicators - avgprice
#77 achieve 100% test coverage for indicators - bollingerbands
#77 achieve 100% test coverage for indicators - cci